Punching tool



p 3, 1964 A. A. CROOKSTON 3,147,550

PUNCHING TOOL.

Filed Aug. 2, 1965 INVENTOR.

AlberZ'A Uroohsl'on BY 93M, W M

ATTORNEYS United States Patent 3,147,550 YUNCHING TGOL Albert A. Crookston, 2257 Springfield Center Road, Akron 12, Ohio Filed Aug. 2, 1963, Ser. No. 299,615 4 Claims. (Cl. 30366) The invention relates to punching tools for punching holes in sheet metal and the like for the insertion of rivets, screws, bolts and similar fastening devices.

Under present shop practice it is customary to use a drill press or punch press for forming apertures in sheet metal parts to accommodate rivets, screws, bolts, and the like for attaching the parts together.

A primary object of the invention is the provision of a small, relatively inexpensive, portable, manually operable tool for easily and readily punching holes in sheet metal.

Another object of the invention is to provide a tool of this type which may be handled and operated like a pistol.

A further object of the invention is to provide a punching tool having a pistol-grip handle and an operating lever for manual operation of the punch.

A still further object of the invention is to provide such a tool including a barrel, to which the pistol-grip handle is attached, and a spring-loaded punch plunger slidable within the barrel and adapted to be released by the operating lever.

It is also an object of the invention to provide a punching tool of the character referred to in which a catch, pivotally mounted on the operating lever, engages a shoulder on the plunger for retracting the plunger and compressing the spring, and guide rods are engaged by the catch for disconnecting it from the plunger at a predetermined time, whereupon the compressed spring will project the plunger forward with considerable force drivin g the punch through the work.

The above objects together with others which will be apparent from the drawing and following description, or which may be later referred to, may be attained by constructing the improved punching tool in the manner hereinafter described in detail and illustrated in the accompanying drawing.

In general terms, the invention may be briefly described as comprising a portable, manually operable, punching tool comprising a pistol-grip handle with tubular barrel carried thereby and a spring-loaded punch plunger slidably located within the barrel.

A pivoted operating lever has a catch thereon in the form of a rod pivotally connected thereto and located through an elongated slot in the handle and having a cross head thereon adapted to engage a shoulder, such as an enlarged head, upon the rear end of the plunger.

Rearwardly and downwardly inclined, or curved, guide rods are provided for contact with the cross head of the catch to disengage the same from the plunger when the spring has been compressed so as to release the plunger, permitting the compressed spring to project the plunger forwardly with sutficient force to drive the punch through the sheet metal part or parts to be punched.

Apreferred embodiment of the invention is illustrated in the accompanying drawing, in which;

FIG. 1 is a side elevation, showing the pivoted catch engaged with the shoulder on the plunger preparatory to operating the operating lever, to retract the plunger and compress the spring;

FIG. 2 is a similar view showing the operating lever pulled toward the handle with the spring compressed and the plunger retracted just prior to the time the guide rods have caused the catch to become disengaged from the shoulder of the plunger; and

3,147,550 Patented Sept. 8, 1964 FIG. 3 is a top plan view showing the parts in the position of FIG. 1.

Referring now more particularly to the embodiment of the invention illustrated, in which similar numerals refer to similar parts throughout, the improved punching tool to which the invention pertains comprises a body portion indicated at 1, having a pistol-grip handle 2 formed integrally therewith, or rigidly connected thereto.

A tubular barrel 3 is located through the body 1 and rigidly mounted thereon, the greater portion of the barrel extending forwardly from the body portion, while a short portion of the barrel extends rearwardly therefrom.

The punch 4, which may be of hardened metal of any suitable shape, is integrally formed upon, or rigidly connected to, the forward end of the plunger rod 5 which is slidably located through the tubular barrel 3 and provided at its rear end with a head 6 having a shoulder 7 normally engaging the rear end of the barrel 3, as shown in FIG. 1.

A pin 8, located transversely through the rod 5, extends through the longitudinal slots 99, in the upper and lower sides of the barrel 3. A disc 10, with central aperture therein, is slidably mounted upon the barrel 3 and is held against the pin 8 by means of the coil spring 11, interposed between said disc and the adjacent or front end of the body 1.

An operating lever 12 is pivoted, as at 13, upon the body 1 and the catch rod 14 is pivotally connected thereto as at 15. The rod 14 is located through the slot 16, in the upper portion of the pistol-grip handle 2, and is provided at its rear end with the cross head 17.

A notch 18 is formed in the underside of the barrel 3, at the rear end thereof, to receive the cross head 17 in contact with the shoulder 7 of the head 6, on the rear end of the plunger, as shown in FIG. 1.

A pair of downwardly and rearwardly inclined, or curved, guide rods 19 are welded, or otherwise rigidly attached, to the body 1 and extend rearwardly and downwardly therefrom.

In the operation of the device, the pivoted catch rod 14 is raised to the position shown in FIG. 1, locating the cross head 17 thereof in the notch 18, on the underside of the barrel 3, and against the shoulder 7 of the head 6 on the rear end of the punch plunger.

The pistol-grip handle 2 is then grasped in the hand and the fingers are located around the operating lever 12 and as the trigger is squeezed toward the pistol-grip handle, through the pivoted catch rod 14, cross head 17 and shoulder 7, the punch plunger 5 will be retracted, compressing the coil spring 11.

The cross head 17 of the catch contacting the undersides of the inclined guide rods 19 will gradually move the cross head downward to the position shown in FIG. 2, at which time the plunger 5 is fully retracted and the spring 11 fully compressed.

Further rearward movement of the operating lever 12 will cause the cross head 17 of the catch to be moved downward upon the guide rods 19, out of engagement with the shoulder 7 on the head of the plunger, thus releasing the plunger so that the compressed spring 11 will project it forward with considerable force, whereby the punch 4 will puncture the sheet metal at the desired point toward which the barrel 3 is aimed or directed. The shoulder 7 of the head 6 striking the rear end of the barrel 3 limits the forward movement of the punch plunger.

This operation may be repeated easily and rapidly to punch any desired number of holes at desired points on the work.

It will be seen that the improved punching tool provides a simple, inexpensive and easily operated device for readily and economically punching holes in sheet metal parts for inserting rivets, bolts, screws or the like.

The tool being light in weight and manually operated, permits its use anywhere in the field or shop for rapidly punching holes at any desired point in the work, the tool being handled and operated in the same manner as a pistol, the barrel being aimed at the point on the work where it is desired to punch a hole, the operating lever being operated in the manner of a trigger of a gun.

It will furthermore be obvious that there are certain inherent advantages in punching holes in sheet metal for rivets, bolts or screws, rather than drilling such holes.

When a hole is drilled, a certain amount of stock is removed from the point where the fastener is inserted, and where the required strength of the joint is desired.

On the contrary, where a hole is punched it is formed by the moving of stock, not the removal thereof, thus producing a metal flow which forms a collar around the hole, which when mated, especially when punched together, produces a joint of greater strength. This is true whether used with a rivet or a bolt.

Also, in the case of self-tapping screws, such collar forms a base for the threads, which is not obtainable in a drilled hole.

In the foregoing description certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. A punching tool including a body portion, a tubular barrel located through said body portion, a plunger rod slidably located through said barrel, a punch upon the forward end of said plunger rod, a transversely disposed pin located through the forward end portion of said plunger rod, there being longitudinal slots in said tubular barrel through which said pin is movably located, a coil spring around said barrel between said pin and said body portion normally urging said plunger rod forward, a pistol-grip handle rigidly connected to said body portion and extending downwardly therefrom, an operating lever pivotally mounted upon said body portion forward of said handle, a catch pivotally mounted upon said operating lever, a head at the rear end of said plunger rod for engagement by said catch, whereby movement of said operating lever toward said handle will cause compression'of said spring, and guide rod means extending rearwardly from said body portion for disengaging said catch from said head when said spring is compressed to cause said spring to forcibly project said plunger rod forwardly.

2. A punching tool including a body portion, a tubular barrel located through said body portion, a plunger rod slidably located through said barrel, a punch upon the forward end of said plunger rod, a transversely disposed pin located through the forward end portion of said plunger rod, there being longitudinal slots in said tubular barrel through which said pin is movably located, a coil spring around said barrel between said pin and said body portion normally urging said plunger rod forward, a pistol-grip handle rigidly connected to said body portion and extending downwardly therefrom, an operating lever pivotally mounted upon said body portion forward of said handle, a catch comprising a rod pivotally mounted upon said operating lever and having a cross head at its rear end, a shoulder at the rear end of said plunger rod for engagement by said cross head, whereby movement of said operating lever toward said handle will cause compression of said spring, and spaced guide rods extending rearwardly and downwardly from said body portion for contacting said cross head and disengaging it from said shoulder when said spring is compressed to cause said spring to forcibly project said plunger rod forwardly.

3. A punching tool including a body portion, a tubular barrel located through said body portion, the greater portion of said barrel extending forwardly from said body portion, a plunger rod slidably located through said barrel, a punch upon the forward end of said plunger rod, a transversely disposed pin located through the forward end portion of said plunger rod, there being longitudinal slots in said tubular barrel through which said pin is movably located, a coil spring around said barrel between said pin and said body portion normally urging said plunger rod forward, a pistol-grip handle rigidly connected to said body portion and extending downwardly therefrom, an operating lever pivotally mounted upon said body portion forward of said handle, a catch comprising a rod pivotally mounted upon said operating lever and having a cross head at its rear end, there being a slot in said pistol-grip handle through which said catch rod is located, a shoulder at the rear end of said plunger rod for engagement by said ,cross head, whereby movement of said operating lever toward said handle will cause compression of said spring, and spaced guide rods extending rearwardly and downwardly from said body portion for contacting said cross head and disengaging it from said shoulder when said spring is compressed to cause said spring to forcibly project said plunger rod forwardly.

4. A punching tool including a body portion, a tubular barrel located through said body portion, a plunger rod slidably located through said barrel, a punch upon the forward end of said plunger rod, a transversely disposed pin located through the forward end portion of said plunger rod, there being longitudinal slots in said tubular barrel through which said pin is movably located, a coil spring around said barrel between said pin and said body portion normally urging said plunger rod forward, a pistol-grip handle rigidly connected to said body portion and extending downwardly therefrom, an operating lever pivotally mounted upon said body portion forward of said handle, a catch comprising a rod pivotally mounted upon said operating lever and having a cross head at its rear end, a head at the rear end of said plunger rod for engagement by said cross head, whereby movement of said operating lever toward said handle will cause compression of said spring, and spaced guide rods extending rearwardly and curved downwardly from said body portion for contacting said cross head and disengaging it from said head when said spring is compressed to cause said spring to forcibly project said plunger rod forwardly.

References Cited in the file of this patent UNITED STATES PATENTS 1,874,460 Cox Aug. 30, 1932 2,359,699 Valentine Oct. 3, 1944 2,470,891 Hammers May 24, 1949 2,787,179 Warner Apr. 2, 1957 

1. A PUNCHING TOOL INCLUDING A BODY PORTION, A TUBULAR BARREL LOCATED THROUGH SAID BODY PORTION, A PLUNGER ROD SLIDABLY LOCATED THROUGH SAID BARREL, A PUNCH UPON THE FORWARD END OF SAID PLUNGER ROD, A TRANSVERSELY DISPOSED PIN LOCATED THROUGH THE FORWARD END PORTION OF SAID PLUNGER ROD, THERE BEING LONGITUDINAL SLOTS IN SAID TUBULAR BARREL THROUGH WHICH SAID PIN IS MOVABLY LOCATED, A COIL SPRING AROUND SAID BARREL BETWEEN SAID PIN AND SAID BODY PORTION NORMALLY URGING SAID PLUNGER ROD FORWARD, A PISTOL-GRIP HANDLE RIGIDLY CONNECTED TO SAID BODY PORTION AND EXTENDING DOWNWARDLY THEREFROM, AN OPERATING LEVER PIVOTALLY MOUNTED UPON SAID BODY PORTION FORWARD OF SAID HANDLE, A CATCH PIVOTALLY MOUNTED UPON SAID OPERATING LEVER, A HEAD AT THE REAR END OF SAID PLUNGER ROD FOR ENGAGEMENT BY SAID CATCH, WHEREBY MOVEMENT OF SAID OPERATING LEVER TOWARD SAID HANDLE WILL CAUSE COMPRESSION OF SAID SPRING, AND GUIDE ROD MEANS EXTENDING REARWARDLY FROM SAID BODY PORTION FOR DISENGAGING SAID CATCH FROM SAID HEAD WHEN SAID SPRING IS COMPRESSED TO CAUSE SAID SPRING TO FORCIBLY PROJECT SAID PLUNGER ROD FORWARDLY. 